Bleaching compound



Patented Apr. 6, 1937 TENT 0pm BLEACHING COMPOUND Pedro Sanchez, Buflalo, N. Y.

No Drawing. Application June 11, 1.84, Serial No. 730,154

com

This invention relates to solid bleaching compounds adapted to form active bleaching agents in solution together with substances insoluble in the solution that present a substantially large contact surface, and more particularly to bleaching compounds including active chlorine in combination and a substance capable of combining metathetically therewith to form a material insoluble in the solution.

In the bleaching oi certain organic substances, such as animal or vegetable substances, or where certain color compounds present in a-substance are desired to be changed to uncolored compounds or compounds of less color, a inqst desirable'bleaching condition is that where substantially no mineral matter is added to the material under treatment. In general, the improved bleaching compounds of this invention include active chlorine in combination with another substance and a material capable of combining chemically with such substance to produce a water insoluble material thereby removing substantially all the mineral matter from such solution but leaving a water solution having a high bleaching and decolorizing eiliciency 5 tree P205 content. A bleaching compound 01" and after the action thereof, leaving a minimum of foreign material.

The improved bleaching compound includes, therefore, intimate combinations of substantially dry solid materials capable oi forming an active bleaching agent in contact with water or other suitable solvent; such bleaching compounds are advantageously used for many purposes since they can be made remote from the point of use, or, can be prepared in situ and the constituents thereof varied in accordance with the conditions under which the bleaching compound is used and to conform with the demand required.

As an example of the improved bleaching compound, an active chlorine containing material, such as a hypochlorite of a metallic ion such as calcium, strontium, barium, magnesium, aluminum and thelike, is included in a mixture containing a solid acid, or an acid salt, capable of forming in water an insoluble compound with the metallic ions above enumerated and forming in the water a water soluble compound containing active chlorine, such as a hypochlorous acid, leaving a minimum oi. mineral matter dissolved.

As an example about 100 pounds of bleaching powder is homogeneously mixed with about 50 pounds of so-called "super phosphate" that is, mono calcium phosphate Cal-14600:, o! 45% this approximate composition provides, when in contact with water, a voluminous precipitate oi calcium phosphate, and substantially all of the calcium ions and phosphate ions are removed since these quantities are present in substantially chemically equivalent proportions and produces an aqueous solution containing substantially no soluble mineral salt. That is, substantially all the lime and all the phosphate are precipitated as calcium phosphate producing a solution which I may have variably a pH of 4.5 to 9, although these limits are illustrative only and are not to be deemed a limitation, while the major proportion of hypochlorite is present as free hypochlorous acid. Although super phosphate or an acid phosphate is preferable, other acids such as oxalic or boric acid or acid salts, capable of precipitating the metal ion of the solid hypochlorite may be used.

- In certain decolorizing operations where strict control is maintained upon the acidity of the'solution and a definite pH is required in the operation of the decolorizing process, it may be necessary to vary the quantities of the constituents in the mixture over a fairly wide range or, add to the mixture a pH controlling agent in suflicient quantity to obtain, when the bleaching compound is added to water, an aqueous solution of the desired pH. To this end the pH controlling compound, either acid or alkaline in nature depending upon the condition desired, is added in suitcient quantity to control the production of the desired solution. As an example, additions of lime or similar alkaline agents are added to a mixture normally producing a solution of a low pH, that is, less than 7, to control the pH of the resulting solution at the desired point, forinstance, a pH of 7 or above. Where the conditions of treatment require a treating solution of pH less than '7 an amount of acid or acid salt is included to produce the desired hydrogen ion concentration. The resulting solution contains substantially pure hypochlorous acid in an ash free condition being substantially free of mineral salts and being in a relatively stable form when compared to the hypochlorous acid solutions prepared heretofore.

What is claimed is:

1. A decoloriiiingv reagent in powdered form consisting of substantially equivalent amounts of calcium hypochlorite and mono calcium phosphate.

2. A decolorizing reagent in powdered form consisting of calcium hypochlorite and soluble calcium phosphate in amounts to precipitate substantially all the calcium as insoluble calcium phosphate when added to water.

PEDRO SANCHEZ. 

